NEN EN 13959 : 2004

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
   3.1 Anti-pollution check valves
   3.2 Flanged anti-pollution check valves; class a and
         class b
   3.3 Combined product
4 Nominal size
5 Designation
6 Marking and technical documents
   6.1 Marking
   6.2 Technical documents
7 Symbolization
8 General design characteristics
   8.1 Overall length and diameters of check valves
   8.2 End connections
   8.3 Test and drain ports
   8.4 Other characteristics
9 Physio-chemical characteristics
   9.1 Materials
   9.2 Nature of materials
10 Test Arrangements
   10.1 Sequence of testing
   10.2 Apparatus
11 Hydraulic and mechanical characteristics
   11.1 High velocity (stage 1)
   11.2 Flow rate/pressure loss (stage 2)
   11.3 Mechanical strength of the body (stage 3)
   11.4 Bending moment (stage 4)
   11.5 Pressure tightness under a low reverse pressure
         differential (stage 5)
   11.6 Pressure tightness under a high reverse pressure
         and verification that the check valve has not
         jammed (stage 6)
   11.7 Pressure differential at which the check valve
         closes (stage 7)
   11.8 Compatibility with products used for disinfection
         of networks (stage 8)
   11.9 Endurance (stage 9)
   11.10 Pressure tightness under a low reverse pressure
         differential (stage 10)
   11.11 Pressure tightness under a high reverse pressure
         and verification that the check valve has not
         jammed (stage 11)
   11.12 Pressure differential at which the check valve
         closes (stage 12)
12 General working characteristics
   12.1 Resistance to corrosion
   12.2 Acoustic characteristics
13 Presentation at delivery
Annex A (informative) Numbers of test devices/tests

Describes the characteristics of anti-pollution check valves of DN 6 up to and including DN 250 that are suitable for use in drinking water systems.